Our objective is to use monoclonal antibodies to elucidate the morphological and functional basis of defective gene action in the retina of visually defective mutant mice. Currently, over 25 different mouse mutants have been found to either lack or have abnormal optokinetic nystagmus. These mutants can be divided into those with histologically normal retinae (mainly hypopigmentation mutants) and those with histologically abnormal retinae (retinal degeneration mutants). The hypopigmentation mutants are interesting because they are congenic to the wild type mouse and they may have well defined functional defects (light sensitivity) in a tissue (retina) that is easily isolated. The retinal degeneration mutants are also congenic to their control and have a functional or developmental defect that results in the degeneration of their outer retina. One of the steps in solving these problems is to try to identify antigens that are different between mutant and normal mice. This will be accomplished by first making monoclonal antibodies to mouse retina and characterizing them in adult and developing normal mice. Then comparing the labeling patterns in the normal animal to the labeling patterns in the mutant animals. A variation of the standard in vivo immunization methods is also being used, the immunosuppression and in vitro immunization technique. By immunizing with tissue from the mutant, suppressing against it, and then reimmunizing later in vitro it is possible to generate antibodies to the molecular differences between mutant and normal tissue or between two different functional states, for instance light-adaptation vs. dark-adaptation. Using a rodless immunogen followed by a dark-adapted retina immunogen, this protocol produced an antibody to dark-adapted rod outer segments. Several other antibodies showing functional dependent labeling have been found and are now being analyzed. In addition, an antibody may label the ribbon synapse in both the outer plexiform layer and the inner plexiform layer; the labeling of B16 will be examined at the ultrastructural level.